This invention relates to computer systems in general and more particularly, to a communications protocol for a system in which two control units communicate with each other.
In large computer systems, and particularly in systems which provide graphics displays, a plurality of different types of peripheral devices for providing input to the computer system are provided. For example, a single system may have as inputs a keyboard, a mouse, a tablet, a light pen, dial boxes, switch boxes and so forth. In a system with a plurality of such peripherals it is advantageous to have a device which can collect inputs from each of these peripherals and then retransmit the various inputs over a single line to the computer system. Such a device is referred to herein as a peripheral repeater box in that it acts as a repeater for each of the individual peripherals.
In such a system there is a need to establish data protcols for the peripheral box to communicate with the peripherals and with the computer system. Ideally, such should be simple, trouble-free and efficient.